Propeller.



A. WAKEFIELD;

PROPELLER.

APPLICATION FILED DEC. 6. 1915.

1,206,058. 4 PatentedNov. 28,1916.

UNITED STATES PATENT OFFICE.

ALBERT WAKEFIELD, OF WASHINGTON, DISTRICT OF COLUMBIA.

PROZPELLER.

Application filed December 6, 1915.

To all whom it may concern its object is to provide a propeller of novel and improved design whereby a maximum efficiency is obtained.

In order that the invention may be better understood, reference is had to the accompanying drawing, in which Figurel is a side elevation of the propeller; Fig. 2 is an end view thereof, and Fig. 3 is an end view of one of the propeller blades showing a modified structure.

Referring specifically to the drawing, 10 denotes a hub or shaft from which the blades of the propeller radiate, said blades being formed integral with the hub, or made separate therefrom and rigidly secured in any approved manner. The drawing shows a six-bladed propeller, the blades being set, obliquely as usual The blades are arranged in staggered order so that each blade is given its own water and there is no interference between the blades. It will be understood, of course, that the number of blades employed may be'varied.

The back of each blade, throughout its entire length, from the hub to the tip, is flat, this portion of the blade being indicated at 11, and extending from the leading edge 12 of the blade up to within a short distance from the back or following edge 12*, the blade being then given a slight transverse curvature, as indicated at 13, this curvature extending throughout the entire length of the blade and from the fiat portion 11 upto the back edge 12*, and the convexity being on the back or rear face of the blade;

On the driving face or side of the blade are parallel longitudinal corrugations or ridges 14 extending from the hub portion of the blade to the tip. These corrugations define a series of inclines 15 sloping in opposite directions, the last inclines merging with the edges of the blade. The driving Specification of Letters Patent.

Patented Nov. 28, 1916.

Serial No. 65,384.

face is thus given a series of working sur faces resulting in a powerful thrust on the medium in which the propeller works, and obtaining a maximum driving force. It will be noted in Fig. 3 that the spacing of the working surfaces from the back of the blade is not uniform but increases from the leading to the following edge. Each working surface is therefore offset relative to the next one, and is thus given its own water, and there is no interference between said surfaces. The corrugations are highest at the following edge of the blade, and they progressively decrease in height toward the leading edge, so that the cross section of the blade is that of a wedge. The faces of the corrugations on the following edge of the blade have a steeper inclination as compared with those of the leading edge. The blade may be made solid, or hollow as shown in Fig. 3.

I claim 1. A propeller blade having on its driving face a series of corrugations, the faces of the corrugations on the following edge of the blade having a steeper inclination as compared with those of the leading edge.

2. A propeller blade having on its driving face a series of corrugations, the faces of the corrugations on the following edge of the blade having a steeper inclination as compared with those of the leading edge, and said corrugations being ofi'set relative to each other.

3. A .propeller blade which is wedge- .shaped in cross-section, the taper being to- ALBERT WAKEFIELD.

mark

Witnesses:

EMILY F. CAMP, ANNIE R. WALTON. 

